Irs (Independent Rear Suspension) In 205

[welshpug 1,658]

yup most of colins setups are 1-1 where possible, some of the race cars he's done can't have turrets so they'll be slightly different but still better than the standard ratio and placement.

[Tom Fenton 1,542]

That beam may be fitted to later Escorts, but for sure Mk 3 and 4 have this arrangement, transverse arms with forward tie rods.

 

[Batfink 201]

The Colin Satchel setup just tackles the issue of crap damper ratio though, right? It doesn't do anything for poor geometry when cornering?

 

What is the new damper ratio with the CS setup? I imagine it gets close to 1:1 if it picks up off the back of the stub axle.

 

It works good enough that i've never driven it thinking I need more rear grip. If business ever picks up I'll get the new chassis going on slicks and see if that makes a difference.

[Cameron 16]

Yep, I'll 100% agree that while you have McPherson struts up front on lowered suspension that you won't suffer by having a loose rear end (oo-err). Saying that, there are huge benefits to be had by replacing the incredibly heavy rear beam and trailing arms.

[welshpug 1,658]

is it really that heavy though?

 

how much would its replacement weigh and how strong would it be compared to the original beam ?

[Cameron 16]

Rear beam weighs a lot! I don't know exactly how much but minus wheels it must easily be 50kg!

 

Depends what you replace it with but you could very easily make something for half the weight. My complete double wishbone rear setup without wheels should happily come in under 20kg and comfortably at the same stiffness.

Edited August 9, 2011 by Cameron

[Anthony 1,003]

Bare rear beam without brakes, hubs, stub axles etc (ie all the bits that'll be common) is going to be somewhere in the region of about 35kg I'd imagine.

 

Given the added complexity and with enough strength built in, I'm not convinced that you'll actually save a huge amount of weight.

 

EDIT - just been out and weighed a complete 309 GTi beam as removed from the car with mounts, shocks etc still fitted, and that was roughly 44kg (done on bathroom scales, so give or take a few percent). 205 width beam will be a touch less than that due to the thinner bars and narrower width

Edited August 9, 2011 by Anthony

[Sandy 191]

Colin's set up uses revised rear toe and camber, can't tell you exactly how though! Revised arm angle on the next generation he's working on now too. Combined with the front (entirely revised geometry, roll centre and bump steer especially), it's amazingly effective, you really can't appreciate how good it is, unless you've tried it. The steering precision and linearity of repsonse is in another league to normal 205s, the roll is very controlled and ride comfort bizarrely brilliant and on the edge it's just playful and precise. I'm a really fussy chassis nit picker, driven alot of lauded road and competition cars and don't hand out praise like that without good reason.

 

It makes me sad to see people labouring on with massively expensive dampers etc on beefed up std geometry basically!

 

If you've got that old Retro issue his hillclimber was featured in, read the tester's remarks, I paraphrase... the friendliest competition car he'd driven.

Edited August 9, 2011 by Sandy

[stu8v 68 1 Cars]

[Cameron 16]

Bare rear beam without brakes, hubs, stub axles etc (ie all the bits that'll be common) is going to be somewhere in the region of about 35kg I'd imagine.

 

Given the added complexity and with enough strength built in, I'm not convinced that you'll actually save a huge amount of weight.

 

EDIT - just been out and weighed a complete 309 GTi beam as removed from the car with mounts, shocks etc still fitted, and that was roughly 44kg (done on bathroom scales, so give or take a few percent). 205 width beam will be a touch less than that due to the thinner bars and narrower width

 

Sounds about right, bloody heavy in other words!

 

A properly designed replacement can be much lighter, get some wishbones under there instead of trailing arms and you remove the need for incredibly beefed up pivot shafts etc to cope with the offset loadings.

[welshpug 1,658]

you'll see the turret welded in on this thread

 

http://forum.205gtidrivers.com/index.php?showtopic=86566

[Liquid_106 97 1 Cars]

Not worth the hassle for the small benefits of McPherson struts (which are still massively flawed).

Moving back to the front end, how about nicking the revoknuckle off a focus, might be less work to make fit than full double wishbones. Not the ultimate solution, but a step closer? (probably completely the wrong shape/size )

Edited August 9, 2011 by Liquid_106

[feb 47]

Moving back to the front end, how about nicking the revoknuckle off a focus, might be less work to make fit than full double wishbones. Not the ultimate solution, but a step closer? (probably completely the wrong shape/size ;p

 

Having driven a Focus RS I don't know what's all the fuss about the revo knuckle. The car was not pleasant to drive, there was a lot of torque steer and you had to keep making corrections with the steering all the time in order to go straight.

On the other hand a Megane 250 that I drove was brilliant with no torque steer at all.

IIRC it was Renault who developed the system first and Ford copied it and gave it a different name.

[Liquid_106 97 1 Cars]

Having driven a Focus RS I don't know what's all the fuss about the revo knuckle. The car was not pleasant to drive, there was a lot of torque steer and you had to keep making corrections with the steering all the time in order to go straight.

On the other hand a Megane 250 that I drove was brilliant with no torque steer at all.

IIRC it was Renault who developed the system first and Ford copied it and gave it a different name.

Haven't driven either so can't comment, but reviews suggest it is the best thing since sliced bread - probably talking out my arse usual.......

[Cameron 16]

From looking at how the Revoknuckle actually works, the only thing it does is reduce torque steer by reducing the scrub radius (google it). This basically reduces the effective lever arm between the tyre centre (where tractive force is applied) and the kingpin axis, reducing the steering feedback.

 

It's a pretty innovative solution, but it doesn't do much at all to address the other shortfalls of McPherson struts, the biggies being poor camber and toe control. Since torque steer isn't a massive issue with a 205 (remember Ford developed it to address torque steer with some 400-odd Nm) I think it's a pretty pointless exercise trying to fit it to one.

[foreigner 0]

guys I really appreciate all the input gone into this thread.

 

However is there anyone with Mcpherson struts at the back ?

 

I just want to know the difference in the real word ?

 

anyone?

[Cameron 16]

I seriously doubt it to be honest, the closest thing will be Colin's set-up.

[Batfink 201]

Colin's set up uses revised rear toe and camber, can't tell you exactly how though! Revised arm angle on the next generation he's working on now too. Combined with the front (entirely revised geometry, roll centre and bump steer especially), it's amazingly effective, you really can't appreciate how good it is, unless you've tried it. The steering precision and linearity of repsonse is in another league to normal 205s, the roll is very controlled and ride comfort bizarrely brilliant and on the edge it's just playful and precise. I'm a really fussy chassis nit picker, driven alot of lauded road and competition cars and don't hand out praise like that without good reason.

 

It makes me sad to see people labouring on with massively expensive dampers etc on beefed up std geometry basically!

 

If you've got that old Retro issue his hillclimber was featured in, read the tester's remarks, I paraphrase... the friendliest competition car he'd driven.

 

Colin runs soft springs on the back which would naturally give this characteristic. Correct me if i'm wrong but only 140lb off the top of my head. I upgraded to 180lb and for a dedicated track car it was a bit soft still. When I blag my suspension upgrade we will play with massively ramping it up though

[Batfink 201]

guys I really appreciate all the input gone into this thread.

 

However is there anyone with Mcpherson struts at the back ?

 

I just want to know the difference in the real word ?

 

anyone?

 

I doubt there would be any point whatsoever in fitting Mcpherson struts to the rear. With the subframe it would be heavier and you have the same handling issues such as lack of camber control.

The first question you have to ask is what are you trying to achieve?

[thirdtimelucky 3]

guys I really appreciate all the input gone into this thread.

 

However is there anyone with Mcpherson struts at the back ?

 

I just want to know the difference in the real word ?

 

anyone?

 

I have McPherson suspension in the rear of my 4wd. The reason I used it wasn't so much a suspension upgrade, I needed room for the prop and rear dif and also needed to drive the rear wheels. Its a fair bit of work but once its there it gives you more options to adjust the geometry and all the adjustable and uprated parts are on the shelf; bushes, adjustable lower arms, eccentric top mounts and coil-overs with wide range of spring at different rates. The other advantage is you don't have to use ever depleting 205 parts you could use 306 or 206 parts.

 

If you are going to do it your self its doesn't cost much and its an improvement over standard setup but you need the skills in both fabrication and design and have a good understanding of suspension geometry. If your going to go to the expense of paying someone else to make it there are better options. Go with one of Collins tried and tested set-ups or if you have money to burn get someone to make something fully adjustable and bespoke, I'm sure Cameron's design will fit the bill.

[foreigner 0]

I have McPherson suspension in the rear of my 4wd. The reason I used it wasn't so much a suspension upgrade, I needed room for the prop and rear dif and also needed to drive the rear wheels. Its a fair bit of work but once its there it gives you more options to adjust the geometry and all the adjustable and uprated parts are on the shelf; bushes, adjustable lower arms, eccentric top mounts and coil-overs with wide range of spring at different rates. The other advantage is you don't have to use ever depleting 205 parts you could use 306 or 206 parts.

 

 

 

You basically summerised my aims.

[welshpug 1,658]

you're going 4x4 or rwd?

[allye 530 3 Cars]

I have nothing to add but this has been one interesting read! In a sad kind of way.

 

As above, I havnt read the aim or purpose of the interest in this by the thread starter!?

[Sandy 191]

Colin runs soft springs on the back which would naturally give this characteristic. Correct me if i'm wrong but only 140lb off the top of my head. I upgraded to 180lb and for a dedicated track car it was a bit soft still. When I blag my suspension upgrade we will play with massively ramping it up though

 

Are you talking the Rallye? That was done by Mark Shillaber, his own take on Colin's design and not quite the same. I don't think it had the geometry changes Colin applies and Colin usually uses about 185lb/" on the back. The front wasn't anything like Colin's on that one and that makes a big difference.

[foreigner 0]

you're going 4x4 or rwd?

 

neither and either at the same time.

 

I want to have rear suspension I can change bit more and easier and for less money than standard beam.

 

So afterwards if I decide 4x4 or rwd I will have easier job as basically everything is there.

 

 

I have nothing to add but this has been one interesting read! In a sad kind of way.

 

As above, I havnt read the aim or purpose of the interest in this by the thread starter!?

 

The purpose of this thread as of my first post is to find if anyone has got any experience with the front suspension set up at the back. But it got nicely elaborated into rear beam and Colin set up thread which is great.

If you read properly I politely asked only technical input. So what was the technical input on your side ? lol

 

Anyway I got contact for somewhere to have a look so as always this forum is great source of information and help.

Thanx

 

If you have mnore technical stuff to add bring it on.